Special effects in Syfy-type monster movies have really improved in the last 3 or 4 years. Just as recently as the mid 2000's, the effects were often blocky, padly pixellated and rendered into the background and often looked out of place. Slowly but surely, these made-for-TV films are getting better effects, as the price of quality CGI slowly falls. In modern monster films of this type, such as HYDRA and BASILISK, the creatures are now routinely very well created, although I;ve noticed how the CGI is low quality in things such as backgrounds, explosions, weather etc.
But quality special-effects do not a good picture make; story, characters, script, and a bit of sense also help too.
HYDRA - THE LOST ISLAND is basically yet another copy of THE MOST DANGEROUS GAME with a mythical creature thrown in. An ex-marine and three criminals are kidnapped and taken to a deserted island where four mega-rich businessmen with grudges have paid to hunt them. However, the island is also home to the four-headed snake-like HYDRA, who doesn't care if its prey is hunter or hunted, it justs wants some dinner.
I quite enjoyed this film actually. The effects are better than usual; not great, but not bad, but the monster isn't really the best thing here. The story, though unoriginal, is well-handled, and is entertaining, and the characters are clearly distinguishable and well-motivated. Generally, for a film with a giant mythical monster in it, this is pretty good, and you could do much much worse than this for some creature-feature thrills.